Naphthyridine derivatives

ABSTRACT

Substituted naphthyridines of the formula (1): ##STR1## wherein one of A, B, C, or D is N, and the others are CR 1  ; 
     R 1  and R 2  are independently H or halo. 
     X, Y and Z are defined in the specification.

This application is a continuation of U.S. Ser. No. 07/385,841, filed Jul. 27, 1989, abandoned.

FIELD OF THE INVENTION

This invention provides new compounds that have excellent plant fungicide activity. Some of the compounds have also demonstrated insecticidal and miticidal activity. The invention also provides compositions and combination products that contain a compound of the invention as active ingredient, as well as providing fungicidal, miticidal, and insecticidal methods.

There is an acute need for new fungicides, insecticides, and miticides, because target pathogens are rapidly developing resistance to currently used pesticides. Widespread failure of N-substituted azole fungicides to control barley mildew was observed in 1983, and has been attributed to the development of resistance. At least 50 species of fungi have developed resistance to the benzimidazole fungicides. The field performance of DMI (demethylation inhibitor) fungicides, which are now widely relied on to protect cereal crops from powdery mildew, has declined since they were introduced in the 1970's. Even recently introduced fungicides, like the acylalanines, which initially exhibited excellent control of potato late blight and grape downy mildew in the field, have become less effective because of widespread resistance. Similarly, mites and insects are developing resistance to the miticides and insecticides in current use. Resistance to insecticides in arthropods is widespread, with at least 400 species resistant to one or more insecticides. The developement of resistance to some of the older insecticides, such as DDT, the carbamates, and the organophosphates, is well known. But resistance has even developed to some of the newer pyrethroid insecticides and miticides. Therefore a need exists for new fungicides, insecticides, and miticides.

SUMMARY OF THE INVENTION

This invention provides compounds of the formula (1): ##STR2## wherein

one of A, B, E, or D is N, and the others are CR¹ ;

R¹ and R² are independently H or halo.

X is O, S, SO, SO₂, NR³, or CR⁴ R⁵, where R³ is H, (C₁ -C₄) alkyl, or (C₁ -C₄) acyl, and R⁴ and R⁵ are independently H, (C₁ -C₄) acyl, (C₁ -C₄) alkyl, (C₂ -C₄) alkenyl or -alkynyl, CN, or OH, or R⁴ and R⁵ combine to form a carbocyclic ring containing four to six carbon atoms;

Y is nil, Z being bonded directly to X, or Y is an alkyl chain one to six carbon atoms long, optionally including a carbocyclic ring, and optionally including a hetero atom selected from O, S, SO, SO₂, NR³, or SiR¹⁹ R²⁰, where R¹⁹ and R²⁰ are independently H, (C₁ -C₄) alkyl, (C₃ -C₄) branched alkyl, phenyl, or substituted phenyl, and optionally substituted with (C₁ -C₄) alkyl, (C₂ -C₄) alkenyl or -alkynyl, branched (C₃ -C₇) alkyl, (C₃ -C₇) cycloalkyl or -cycloalkenyl, halo, hydroxy, or acetyl, and

Z is

(a) a C₁ -C₁₂ saturated or unsaturated hydrocarbon chain, straight chain or branched optionally including a hetero atom selected from O, S, SO, SO₂, NR³, or SiR¹⁹ R²⁰, and optionally substituted with halo, halo (C₁ -C₄) alkoxy, hydroxy, (C₃ -C₈) cycloalkyl or cycloalkenyl, or (C₁ -C₄) acyl;

(b) (C₃ -C₈) cycloalkyl or cycloalkenyl, optionally substituted with (C₁ -C₄) alkyl, (C₁ -C₄) alkoxy, halo (C₁ -C₄) alkyl, halo (C₁ -C₄) alkoxy, halo, hydroxy, or (C₁ -C₄) acyl;

(c) a phenyl group of the formula (2) ##STR3## where

R⁶ to R¹⁰ are independently H, halo, I, (C₁ -C₁₀) alkyl, (C₃ -C₈) alkenyl or -alkynyl, branched (C₃ -C₆) alkyl, -alkenyl, or -alkynyl, (C₃ -C₈) cycloalkyl or -cycloalkenyl, halo (C₁ -C₇) alkyl, (C₁ -C₇) alkoxy, (C₁ -C₇) alkylthio, halo (C₁ -C₇) alkoxy, phenoxy, substituted phenoxy, phenylthio, substituted phenylthio, phenyl, substituted phenyl, NO₂, acetoxy, OH, CN, SiR¹¹ R¹² R¹³, OSiR¹¹ R¹² R¹³, NR¹⁴ R¹⁵, S(O)R¹⁶, or SO₂ R¹⁷ where R¹¹, R¹², and R¹³ are independently (C₁ -C₄) alkyl, (C₃ -C₄) branched alkyl, phenyl, or substituted phenyl, R¹⁴ and R¹⁵ are independently H, (C₁ -C₄) alkyl, or (C₁ -C₄) acyl, and R¹⁶ and R¹⁷ are phenyl, substituted phenyl, or (C₁ -C₄) alkyl;

(d) a furyl group of formula (3) ##STR4## where

R¹⁸ is H, halo, halomethyl, CN, NO₂, (C₁ -C₄) alkyl, (C₃ -C₄) branched alkyl, phenyl, substituted phenyl, or (C₁ -C₄) alkoxy;

(e) a thienyl group of the formula (4) ##STR5## where

R¹⁸ is as defined in paragraph (d);

(f) a group of formula (5) or (6) ##STR6## where

R¹⁸ is as defined in paragraph (d), J is N or CH, and G is O, NR¹⁹, or S, provided that if J is not N then G is NR¹⁹, where R¹⁹ is H, (C₁ -C₄) alkyl, (C₁ -C₄) acyl, phenylsulfonyl, or substituted phenylsulfonyl;

(g) a group selected from

optionally substituted naphthyl, dihydronaphthyl, tetrahydronaphthyl, and decahydronaphthyl;

optionally substituted pyridyl;

optionally substituted indolyl;

and 1,3-benzodioxolyl;

or an acid addition salt or N-oxide of a compound of formula (1).

The fungicide combinations of the invention comprise at least 1% by weight of a compound of formula (1) in combination with a second plant fungicide.

The fungicide compositions of the invention comprise a disease inhibiting and phytologically acceptable amount of compound of formula (1) in combination with a phytologically-acceptable carrier. Such compositions may optionally contain additional active ingredients, such as an additional fungicidal, miticidal, or insecticidal ingredient.

The fungicidal method of the invention comprises applying to the locus of a plant pathogen a disease inhibiting and phytologically acceptable amount of a compound of formula (1).

The insecticide and miticide combinations of the invention comprise at least 1% by weight of a compound of formula (1) in combination with a second insecticide or miticide.

The insecticide and miticide compositions of the invention comprise an insect- or mite-inactivating amount of a compound of formula (1) in combination with a carrier. Such compositions may optionally contain additional active ingredients, such as an additional fungicidal, miticidal, or insecticidal ingredient.

The insecticidal or miticidal method of the invention comprises applying to a locus of an insect or mite an insect- or mite-inactivating amount of a compound of formula (1), or of a combination described above.

DETAILED DESCRIPTION OF THE INVENTION

Throughout this document, all temperatures are given in degrees Celsius, and all percentages are weight percentages unless otherwise stated.

The term "halo" refers to a F, Cl, or Br atom.

The term "(C₁ -C₇) alkoxy" refers to straight or branched chain alkoxy groups.

The term "(C₁ -C₇) alkylthio" refers to straight and branched chain alkylthio groups.

The term "halo (C₁ -C₇) alkyl" refers to a (C₁ -C₇) alkyl group, straight chain or branched, substituted with one or more halo atoms.

The term "halo (C₁ -C₇) alkoxy" refers to a (C₁ -C₇) alkoxy group substituted with one or more halo groups.

The term "halo (C₁ -C₄) alkylthio" refers to a (C₁ -C₄) alkylthio group, straight chain or branched, substituted with one or more halo atoms.

The term "substituted phenyl" refers to phenyl substituted with up to three groups selected from halo, I, (C₁ -C₁₀) alkyl, branched (C₃ -C₆) alkyl, halo (C₁ -C₄) alkyl, hydroxy (C₁ -C₄) alkyl, (C₁ -C₄) alkoxy, halo (C₁ -C₄) alkoxy, phenoxy, substituted phenoxy, phenyl, substituted phenyl, NO₂, OH, CN, (C₁ -C₄) alkanoyloxy, or benzyloxy.

The terms "substituted naphthyl", "substituted pyridyl" and "substituted indolyl" refer to these ring systems substituted with halo, halo (C₁ -C₄) alkyl, CN, NO₂, (C₁ -C₄) alkyl, (C₃ -C₄) branched alkyl, phenyl, (C₁ -C₄) alkoxy, or halo (C₁ -C₄) alkoxy.

The term "substituted phenoxy" refers to phenoxy substituted with up to three groups selected from halo, I, (C₁ -C₁₀) alkyl, branched (C₃ -C₆) alkyl, halo (C₁ -C₇) alkyl, hydroxy (C₁ -C₇) alkyl, (C₁ -C₇) alkoxy, halo (C₁ -C₇) alkoxy, phenoxy, substituted phenoxy, phenyl, substituted phenyl, NO₂, OH, CN, (C₁ -C₄) alkanoyloxy, or benzyloxy.

The term "carbocyclic ring" refers to a saturated or unsaturated carbocyclic ring containing three to seven carbon atoms.

The terms "substituted phenylthio" and "substituted phenyl sulfonyl" refer to such groups substituted with up to three groups selected from halo, I, (C₁ -C₁₀) alkyl, branched (C₃ -C₆) alkyl, halo (C₁ -C₇) alkyl, hydroxy (C₁ -C₇) alkyl, (C₁ -C₇) alkoxy, halo (C₁ -C₇) alkoxy, phenoxy, substituted phenoxy, phenyl, substituted phenyl, NO₂, OH, CN, (C₁ -C₄) alkanoyloxy, or benzyloxy.

The term "unsaturated hydrocarbon chain" refers to a hydrocarbon chain containing one or two sites of unsaturation.

The term "HPLC" refers to a high-performance liquid chromatography.

COMPOUNDS

While all of the compounds of the invention are useful fungicides, certain classes are preferred for reasons of greater efficacy or ease of synthesis, viz:

(a) compounds of formula (1) wherein A is N, i.e., 1,5-naphthyridine derivatives; and

(b) compounds of formula (1) wherein Z is substituted phenyl.

SYNTHESIS

The compounds of this invention are made using well known chemical procedures. The required starting materials are commercially available, or they are readily synthesized using standard procedures.

SYNTHESIS OF COMPOUNDS WHEREIN X IS O

The compounds of formula (1) wherein X is O are made by condensing a compound of formula (7): ##STR7## where R², A, B, E, and D are as previously defined, and L is a leaving group, such as F, Cl, Br, I, NO₂, 1,2,4-triazol-1-yl, O-SiMe₃, arylthio, alkylthio, alkylsulfonyl, arylsulfonyl, alkoxy, or arylsulfinyl with an alcohol or phenol of the formula (8):

    HO--Y--Z                                                   (8)

where

Y and Z are as previously defined.

The reaction is preferably carried out in the presence of a strong base, such as sodium hydride, in a non-reactive organic solvent, such as DMF, at a temperature in the range of 0° to 25° C.

SYNTHESIS OF COMPOUNDS WHEREIN X IS NR³

The compounds of formula (1) wherein X is NR³ are prepared by condensing a compound of formula (7) with an amine of the formula (9) ##STR8## where R³ ' is H or (C₁ -C₄) alkyl, and

Y and Z are as previously defined.

The chloride of formula (7) is allowed to react with an appropriate amine at a wide variety of temperatures (20°-180° C.), preferably in the presence of an acid acceptor, such as triethylamine. The reaction may be carried out neat, or in a non-reactive organic solvent. Compounds where R³ is acyl are prepared from amines where R³ is H, which were allowed to react with an acylating agent such as an acetyl chloride or acetic anhydride. In cases where the starting material of formula (7) is one wherein R¹ or R² is Cl, a mixture of products is obtained which are separable using liquid chromatography.

SYNTHESIS OF COMPOUNDS WHEREIN X IS CR⁴ R⁵

Compounds of formula (1) wherein X is CR⁴ R⁵ are prepared by reacting a compound of formula (7) where L is H with a Grignard reagent of the formula Z--Y--MgX' or a lithio reagent of the formula Z--Y--Li, where X' is halo, to provide a 3,4-dihydro naphthyridine, which is then oxidized. The desired compound of the invention may then be separated from other products using conventional means. Typical reaction conditions are those described in Armarego and Smith, J. Chem. Soc., page 5360 (1965).

The acid addition salts and N-oxides of compounds of formula (1) are obtained in the usual way.

Accordingly, the invention also provides a process for preparing a compound of formula (1) which comprises

(a) condensing a compound of formula (7) ##STR9## wherein R¹, R², A, B, E, and D are as previously defined, and L is a leaving group, with an alcohol of the formula (8):

    HO--Y--Z                                                   (8)

wherein Y and Z are as previously defined to produce a compound of formula (1) wherein X is O; or

(b) condensing a compound of formula (7) as defined above with an amine of the formula (9) ##STR10## where R³ ' is H or (C₁ -C₄) alkyl, and Y and Z are as previously defined, to provide a compound of formula (1) where X is NR³ '; or

(c) acylating a compound of formula (1) wherein X is NR³ ' to provide a compound of formula (1) wherein X is NR³ and R³ is acyl; or

(d) reacting a compound of formula (7) wherein L is H with a Grignard reagent of formula Z--Y--MgX', where X' is halo and Z and Y are as defined above, or with a lithio reagent of formula Z--Y--Li, to provide a 3,4-dihydro naphthyridine, which is then oxidized to produce a compound of formula (1) wherein X is CR⁴ R⁵.

PREPARATION OF NAPHTHYRIDINE STARTING MATERIALS

Naphthyridine starting materials are commercially available or readily prepared using conventional procedures.

For example, 1,7-naphthyridine starting materials can be prepared by the process described by R. Surrey and D. Hammer in J. Am. Chem. Soc. 68, 115 (1946). 1,5- and 1,6-naphthyridines can be prepared by the process described in British Patent 1,147,760 and Chem. Abst. 71, 49967a (1969). 1,8-naphthyridine starting materials are prepared by the process described by W. W. Paulder and D. J. Pokorny in J. Org. Chem. 36, 1720 (1971) and J. Org. Chem. 37, 3101 (1972).

Intermediates of formula (7) wherein L is 1,2,4-triazol-1-yl, can be prepared, for example, by adding POCl₃ dropwise to a mixture of a 4-hydroxynaphthyridine (1 equiv.) and 1,2,4-triazole (3 equiv.) in pyridine at room temperature.

EXAMPLES 1-10

The following examples are compounds actually prepared by the above described general procedures. The melting point is given for each compound. In addition, although the data has not been included, each compound was fully characterized by NMR, IR, mass spectra, and combustion analysis. Specific illustrative preparations for the compounds of Examples 4 and 7 follow the tabular listing.

    ______________________________________                                         EXAMPLE                                                                        NUMBER   COMPOUND              M.P.                                            ______________________________________                                         1        4-(4-fluorophenoxy)-1,8-naphthyridine                                                                131-133° C.                              2        4-(4-fluorophenoxy)-1,7-naphthyridine                                                                169-171° C.                              3        4-(4-fluorophenoxy)-1,6-naphthyridine                                                                79-81° C.                                4        4-(4-fluorophenoxy)-1,5-naphthyridine                                                                122-124° C.                              5        4-[2-[4-(t-butyl)phenyl]ethoxy]-1,5-                                                                 oil                                                      naphthyridine                                                         6        4-[3-(4-ethoxyphenyl)propoxy]-1,5-                                                                   104-105° C.                                       naphthyridine                                                         7        N-[2-[4-(t-butyl)phenyl]ethyl]-1,5-                                                                  oil                                                      naphthyridin-4-amine                                                  8        4-(2-chlorophenoxy)-1,8-naphthyridine                                                                126-128° C.                              9        4-[2-(4-ethoxyphenyl)ethoxy]-1,5-                                                                    65-66° C.                                         naphthyridine                                                         10       N-(2-phenylethyl)-1,5-naphthyridin-4-                                                                100-101° C.                                       amine                                                                 ______________________________________                                    

The procedures described in the following detailed examples are representative of the procedures used to prepare the compounds of the other examples.

EXAMPLE 4 4-(4-fluorophenoxy)-1,5-naphthyridine

A mixture comprising 150 mg (0.911 mmole) of 4-chloro-1,5-naphthyridine and 1.00 g of 4-fluorophenol was heated at 160° C. After one hour, the mixture was cooled and dissolved in ethyl acetate and 2N sodium hydroxide. The organic layer was washed twice with base to remove excess 4-fluorophenol. The organic layer was then dried with magnesium sulfate and concentrated, producing an oil that slowly crystallized. This product was recrystallized in heptane, giving 103 mg of the title product. MP 122°-124° C. Yield 47%.

EXAMPLE 7

N-[2-[4-(t-butyl)phenyl]ethyl]-1,5-naphthyridin-4-amine

A mixture of 500 mg of 4-chloro-1,5-naphthyridine and 1.0 g of N-[2-[4-(t-butyl)phenyl]ethyl]amine was stirred at 130° C. for 30 minutes. Then a 50/50 mixture of ammonium hydroxide and water was added. The product was extracted into methylene chloride, which was then concentrated. The product was purified by HPLC (silica gel, 20% ethyl acetate/80% pentane). The fractions containing the major product were collected and concentrated giving 0.277 mg of the title product as an oil. Yield 30%.

FUNGICIDE UTILITY

The compounds of the present invention have been found to control fungi, particularly plant pathogens. When employed in the treatment of plant fungal diseases, the compounds are applied to the plants in a disease inhibiting and phytologically acceptable amount. The term "disease inhibiting and phytologically acceptable amount," as used herein, refers to an amount of a compound of the invention which kills or inhibits the plant disease for which control is desired, but is not significantly toxic to the plant. This amount will generally be from about 1 to 1000 ppm, with 10 to 500 ppm being preferred. The exact concentration of compound required varies with the fungal disease to be controlled, the type formulation employed, the method of application, the particular plant species, climate conditions and the like. A suitable application rate is typically in the range from 0.25 to 4 lb/A. The compounds of the invention may also be used to protect stored grain and other non-plant loci from fungal infestation.

GREENHOUSE TESTS

The following experiments were performed in the laboratory to determine the fungicidal efficacy of the compounds of the invention.

TEST 1

This screen was used to evaluate the efficacy of the present compounds against a variety of different organisms that cause plant diseases.

The test compounds were formulated for application by dissolving 50 mg of the compound into 1.25 ml of solvent. The solvent was prepared by mixing 50 ml of "Tween 20" (polyoxyethylene (20) sorbitan monolaurate emulsifier) with 475 ml of acetone and 475 ml of ethanol. The solvent/compound solution was diluted to 125 ml with deionized water. The resulting formulation contains 400 ppm test chemical. Lower concentrations were obtained by serial dilution with the solvent-surfactant mixture.

The formulated test compounds were applied by foliar spray. The following plant pathogens and their corresponding plants were employed.

    ______________________________________                                                         Designation in                                                 Pathogen        Following Table                                                                             Host                                              ______________________________________                                         Erysiphe graminis tritici                                                                      POWD         wheat                                             (powdery mildew)                                                                               MDEW                                                           Pyricularia oryzae                                                                             RICE         rice                                              (rice blast)    BLAS                                                           Puccinia recondita tritici                                                                     LEAF         wheat                                             (leaf rust)     RUST                                                           Botrytis cinerea                                                                               GRAY         grape berries                                     (gray mold)     MOLD                                                           Pseudoperonospora cubensis                                                                     DOWN         squash                                            (downy mildew)  MDEW                                                           Cercospora beticola                                                                            LEAF         sugar beet                                        (leaf spot)     SPOT                                                           Venturia inaequalis                                                                            APPL         apple seedling                                    (apple scab)    SCAB                                                           Septoria tritici                                                                               LEAF         wheat                                             (leaf blotch)   BLOT                                                           ______________________________________                                    

The formulated technical compounds were sprayed on all foliar surfaces of the host plants (or cut berry) to past run-off. Single pots of each host plant were placed on raised, revolving pedestals in a fume hood. Test solutions were sprayed on all foliar surfaces. All treatments were allowed to dry and the plants were inoculated with the appropriate pathogens within 2-4 hours.

Table 1 presents the activity of typical compounds of the present invention when evaluated in this experiment. The effectiveness of test compounds in controlling disease was rated using the following scale.

0=not tested against specific organism

-=0-19% control at 400 ppm

+=20-89% control at 400 ppm

++=90-100% control at 400 ppm

+++=90-100% control at 100 ppm

                                      TABLE 1                                      __________________________________________________________________________     EX.                                         LEAF                                                                               APPL                                                                               LEAF                       NO.                                                                               POWD MDEW                                                                               RICE BLAST                                                                             LEAF RUST                                                                             GRAY MOLD                                                                              DOWN MDEW                                                                               SPOT                                                                               SCAB                                                                               BLOT                       __________________________________________________________________________     1  +        -       ++     -       ++       0   0   0                          2  +        -       +      -       +        0   0   0                          3  -        -       -      -       -        0   0   0                          4  +        +       +      -       ++       0   0   0                          5  +        ++      ++     -       +++      0   0   0                          6  -        -       -      -       -        0   0   0                          7  ++       ++      +++    -       +++      0   0   0                          8  -        +       +      -       ++       0   0   0                          9  +        ++      +++    -       ++       0   0   0                          10 +        +       +      -       + ++     +   +   -                          __________________________________________________________________________

COMBINATIONS

Fungal disease pathogens are known to develop resistance to fungicides. When strains resistant to a fungicide do develop, it becomes necessary to apply larger and larger amounts of the fungicide to obtain desired results. To retard the development of resistance to new fungicides, it is desirable to apply the new fungicides in combination with other fungicides. Use of a combination product also permits the product's spectrum of activity to be adjusted.

Accordingly, another aspect of the invention is a fungicidal combination comprising at least 1% by weight of a compound of formula (1) in combination with a second fungicide.

Contemplated classes of fungicides from which the second fungicide may be selected include:

1) N-substituted azoles, for example propiconazole, triademefon, flusilazol, diniconazole, ethyltrianol, myclobutanil, and prochloraz;

2) pyrimidines, such as fenarimol and nuarimol;

3) morpholines, such as fenpropimorph and tridemorph;

4) piperazines, such as triforine; and

5) pyridines, such as pyrifenox. Fungicides in these five classes all function by inhibiting sterol biosynthesis. Additional classes of contemplated fungicides, which have other mechanisms of action include:

6) dithiocarbamates, such as maneb and mancozeb;

7) phthalimides, such as captafol;

8) isophthalonitrites, such as chlorothalonil;

9) dicarboximides, such as iprodione;

10) benzimidazoles, such as benomyl and carbendazim;

11) 2-aminopyrimidines, such as ethirimol;

12) carboxamides, such as carboxin; and

13) dinitrophenols, such as dinocap.

The fungicide combinations of the invention contain at least 1%, ordinarily 20 to 80%, and more typically 50 to 75% by weight of a compound of formula (1).

INSECTICIDE AND MITICIDE UTILITY

The compounds of the invention are also useful for the control of insects and mites. Therefore, the present invention also is directed to a method for inhibiting an insect or mite which comprises applying to a locus of the insect or mitean insect- or mite-inhibiting amount of a compound of formula (1).

The compounds of the invention show activity against a number of insects and mites. More specifically, the compounds show activity against melon aphid, which is a member of the insect order Homoptera. Other members of the Homoptera include leafhoppers, planthoppers, pear pyslla, apple sucker, scale insects, whiteflies, spittle bugs as well as numerous other host specific aphid species. Activity has also been observed against greenhouse thrips, which are members of the order Thysanoptera. The compounds also show activity against Southern armyworm, which is a member of the insect order Lepidoptera. Other typical members of this order are codling moth, cutworm, clothes moth, Indianmeal moth, leaf rollers, corn earworm, European corn borer, cabbage worm, cabbage looper, cotton bollworm, bagworm, eastern tent caterpillar, sod webworm, and fall armyworm.

Representative mite species with which it is contemplated that the present invention can be practiced include those listed below.

    ______________________________________                                                                        COMMON                                          FAMILY       SCIENTIFIC NAME   NAME                                            ______________________________________                                         ACARIDAE     Aleurobius farinae                                                             Rhizoglyphus echinopus                                                                           Bulb mite                                                    Rhizoglyphus elongatus                                                         Rhizoglyphus rhizophagus                                                       Rhizoglyphus sagittatae                                                        Rhizoglyphus tarsalis                                             ERIOPHYIDAE  Abacarus farinae  Grain rust                                                                     mite                                                         Aceria brachytarsus                                                            Acalitus essigi   Redberry                                                                       mite                                                         Aceria ficus                                                                   Aceria fraaxinivorus                                                           Aceria granati                                                                 Aceria parapopuli                                                              Eriophyes sheldoni                                                                               Citrus bud                                                                     mite                                                         Aceria tulipae                                                                 Aculus carnutus   Peach                                                                          silver mite                                                  Aculus schlechtendali                                                                            Apple rust                                                                     mite                                                         Colomerus vitis   Grape                                                                          erineum                                                                        mite                                                         Eriophyes convolvens                                                           Eriophyes insidiosus                                                           Eriophyes malifoliae                                                           Eriophyes padi                                                                 Eriophyes pruni                                                                Epitrimerus pyri  Pear leaf                                                                      blister mite                                                 Eriophyes ramosus                                                              Eriophyes sheldoni                                                                               Citrus bud                                                                     mite                                                         Eriophyes ribis                                                                Phyllocoptes gracilis                                                                            Dryberry                                                                       mite                                                         Phyllocoptruta oleivora                                                                          Citrus rust                                                                    mite                                                         Phytoptus ribis                                                                Trisetacus pini                                                                Vasates amygdalina                                                              Vasates eurynotus                                                             Vasates quadripedes                                                                              Maple                                                                          bladdergall                                                                    mite                                                         Vasates schlechtendali                                            EUPODIDAE    Penthaleus major  Winter                                                                         grain mite                                                   Linopodes spp.                                                    NALEPELLIDAE Phylocoptella avellanae                                                                          Filbert bud                                                                    mite                                            PENTHALEIDAE Halotydeus destrustor                                             PYEMOTIDAE   Pyemotes tritici  Straw itch                                                                     mite                                                         Siteroptes cerealium                                              TARSONEMIDAE Polyphagotarsonemus latus                                                                        Broad mite                                                   Steneotarsonemus pallidus                                                                        Cyclamen                                                                       mite                                            TENUIPALPIDAE                                                                               Brevipalpus californicus                                                       Brevipalpus obovatus                                                                             Privet mite                                                  Brevipalpus lewisi                                                                               Citrus flat                                                                    mite                                                         Dolichotetranychus floridanus                                                                    Pineapple                                                                      flase spider                                                                   mite                                                         Tenuipalpes granati                                                            Tenuipalpes pacificus                                             TETRANYCHIDAE                                                                               Bryobia arborea                                                                Bryobia practiosa Clover                                                                         mite                                                         Bryobia rubrioculus                                                                              Brown mite                                                   Eotetranychus coryli                                                           Eotetranychus hicoriae                                                                           Pecan deaf                                                                     scorch mite                                                  Eotetranychus lewisi                                                           Eotetranychus sexmaculatus                                                                       Sixspotted                                                                     spider mite                                                  Eotetranychus willametti                                                       Eotetranychus banksi                                                                             Texas                                                                          citrus mite                                                  Oligonychus ilicis                                                                               Southern                                                                       red mite                                                     Oligonychus pratensis                                                                            Banks grass                                                                    mite                                                         Oligonychus ununguis                                                                             Spruce                                                                         spider mite                                                  Panonychus citri  Citrus red                                                                     mite                                                         Panonychus ulmi   European                                                                       red mite                                                     Paratetranychus modestus                                                       Paratetranychus pratensis                                                      Paratetranychus viridis                                                        Petrobia latens   Brown                                                                          wheat mite                                                   Schizotetranychus celarius                                                                       Bamboo                                                                         spider mite                                                  Schizotetranychus pratensis                                                    Tetranychus canadensis                                                                           Four-                                                                          spotted                                                                        spider mite                                                  Tetranychus cinnabarinus                                                                         Carmine                                                                        spider mite                                                  Tetranychus mcdanieli                                                                            McDaniel                                                                       spider mite                                                  Tetranychus pacificus                                                                            Pacific                                                                        spider mite                                                  Tetranychus schoenei                                                                             Schoene                                                                        spider mite                                                  Tetranychus urticae                                                                              Twospotted                                                                     spider mite                                                  Tetranychus turkestani                                                                           Strawberry                                                                     spider mite                                                  Tetranychus desertorum                                                                           Desert                                                                         spider mite                                     ______________________________________                                    

The compounds are useful for reducing populations of insects and mites, and are used in a method of inhibiting an insect or mite population which comprises applying to a locus of the insect or arachnid an effective insect- or mite-inactivating amount of a compound of formula (1). The "locus" of insects or mites is a term used herein to refer to the environment in which the insects or mites live or where their eggs are present, including the air surrounding them, the food they eat, or objects which they contact. For example, plant-ingesting insects or mites can be controlled by applying the active compound to plant parts, which the insects or mites eat, particularly the foliage. It is contemplated that the compounds might also be useful to protect textiles, paper, stored grain, or seeds by applying an active compound to such substance. The term "inhibiting an insect or mite" refers to a decrease in the numbers of living insects or mites; or a decrease in the number of viable insect or mite eggs. The extent of reduction accomplished by a compound depends, of course, upon the application rate of the compound, the particular compound used, and the target insect or mite species. At least an insect-inactivating or mite-inactivating amount should be used. The terms "insect-inactivating amount" and "mite-inactivating amount" are used to describe the amount, which is sufficient to cause a measurable reduction in the treated insect or mite population. Generally an amount in the range from about 1 to about 1000 ppm active compound is used.

In a preferred embodiment, the present invention is directed to a method for inhibiting a mite which comprises applying to a plant an effective mite-inactivating amount of a compound of formula (1) in accordance with the present invention.

MITE/INSECT SCREEN

The compounds of Examples 1-10 were tested for miticidal and insecticidal activity in the following mite/insect screen.

Each test compound was formulated by dissolving the compound in acetone/alcohol (50:50) mixture containing 23 g of "TOXIMUL R" (sulfonate/nonionic emulsifier blend) and 13 g of "TOXIMUL S" (sulfonate/nonionic emulsifier blend) per liter. These mixtures were then diluted with water to give the indicated concentrations.

Twospotted spider mites (Tetranychus urticae Koch) and melon aphids (Aphis gossypii Glover) were introduced on squash cotyledons and allowed to establish on both leaf surfaces. Other plants in the same treatment pot were left uninfested. The leaves were then sprayed with 5 ml of test solution using a DeVilbiss atomizing sprayer at 10 psi. Both surfaces of the leaves were covered until runoff, and then allowed to dry for one hour. Two uninfested leaves were then excised and placed into a Petri dish containing larval southern armyworm (Spodopetra eridania Cramer).

Activity on Southern corn rootworm (Diabrotica undecimpuctata howardi Barber) was evaluated by adding two ml of tap water, a presoaked corn seed, and 15 g of dry sandy soil to a one ounce plastic container. The soil was treated with 1 mL of test solution containing a predetermined concentration of test compound. After six to 12 hours of drying, five 2-3 instar corn rootworm larvae were added to the individual cups, which were then capped and held at 23° C.

After standard exposure periods, percent mortality and phytotoxicity were evaluated. Results for the compounds found to be active are reported in Table 3. The remaining compounds showed no activity. The following abbreviations are used in Table 3:

CRW refers to corn rootworm

SAW refers to Southern armyworm

SM refers to twospotted spider mites

MA refers to melon aphids.

                                      TABLE 3                                      __________________________________________________________________________     Mite/Insect Screen                                                                                   SAW                                                              CRW    CRW    SM & MA                                                                               SAW    SM     MA                                  COMPOUND                                                                               RATE PPM                                                                              RESULTS %                                                                             RATE PPM                                                                              RESULTS %                                                                             RESULTS %                                                                             RESULTS %                           __________________________________________________________________________     1       12.00  0      200    0      0      0                                           24.00  0      400    0      0      0                                   2       12.00  0      200    0      40     30                                          24.00  0      400    0      0      0                                   3       12.00  0      200    0      0      0                                           24.00  0      400    0      0      0                                   4       24.00  0      400    0      80     80                                  5       12.00  0      200    0      100    50                                          24.00  0      400    0      100    80                                  6       12.00  0      200    0      0      0                                           24.00  0      400    0      0      0                                   7       12.00  0      200    0      90     90                                          24.00  0      400    0      100    100                                 8       12.00  0      200    0      0      0                                           24.00  0      400    0      0      0                                   9       12.00  0      200    0      40     100                                         24.00  0      400    0      80     100                                 10      12.00  0      200    0      0      0                                   __________________________________________________________________________

COMPOSITIONS

The compounds of this invention are applied in the form of compositions which are important embodiments of the invention, and which comprise a compound of this invention and a phytologically-acceptable inert carrier. The compositions are either concentrated formulations which are dispersed in water for application, or are dust or granular formulations which are applied without further treatment. The compositions are prepared according to procedures and formulae which are conventional in the agricultural chemical art, but which are novel and important because of the presence therein of the compounds of this invention. Some description of the formulation of the compositions will be given, however, to assure that agricultural chemists can readily prepare any desired composition.

The dispersions in which the compounds are applied are most often aqueous suspensions or emulsions prepared from concentrated formulations of the compounds. Such water-soluble, water-suspendable or emulsifiable formulations are either solids usually known as wettable powders, or liquids usually known as emulsifiable concentrates or aqueous suspensions. Wettable powders, which may be compacted to form water dispersible granules, comprise an intimate mixture of the active compound, an inert carrier and surfactants. The concentration of the active compound is usually from about 10% to about 90% by weight. The inert carrier is usually chosen from among the attapulgite clays, the montmorillonite clays, the diatomaceous earths, or the purified silicates. Effective surfactants, comprising from about 0.5% to about 10% of the wettable powder, are found among the sulfonated lignins, the condensed naphthalenesulfonates, the naphthalenesulfonates, the alkylbenzenesulfonates, the alkyl sulfates, and non-ionic surfactants such as ethylene oxide adducts of alkyl phenols.

Emulsifiable concentrates of the compounds comprise a convenient concentration of a compound, such as from about 50 to about 500 grams per liter of liquid, equivalent to about 10% to about 50%, dissolved in an inert carrier which is either a water miscible solvent or a mixture of water-immiscible organic solvent and emulsifiers. Useful organic solvents include aromatics, especially the xylenes, and the petroleum fractions, especially the high-boiling naphthalenic and olefinic portions of petroleum such as heavy aromatic naphtha. Other organic solvents may also be used, such as the terpenic solvents including rosin derivatives, aliphatic ketones such as cyclohexanone, and complex alcohols such as 2-ethoxyethanol. Suitable emulsifiers for emulsifiable concentrates are chosen from conventional nonionic surfactants, such as those discussed above.

Aqueous suspensions comprise suspensions of water-insoluble compounds of this invention, dispersed in an aqueous vehicle at a concentration in the range from about 5% to about 50% by weight. Suspensions are prepared by finely grinding the compound, and vigorously mixing it into a vehicle comprised of water and surfactants chosen from the same types discussed above. Inert ingredients, such as inorganic salts and synthetic or natural gums, may also be added, to increase the density and viscosity of the aqueous vehicle.. It is often most effective to grind and mix the compound at the same time by preparing the aqueous mixture, and homogenizing it in an implement such as a sand mill, ball mill, or piston-type homogenizer.

The compounds may also be applied as granular compositions, which are particularly useful for applications to the soil. Granular compositions usually contain from about 0.5% to about 10% by weight of the compound, dispersed in an inert carrier which consists entirely or in large part of clay or a similar inexpensive substance. Such compositions are usually prepared by dissolving the compound in a suitable solvent, and applying it to a granular carrier which has been pre-formed to the appropriate particle size, in the range of from about 0.5 to 3 mm. Such compositions may also be formulated by making a dough or paste of the carrier and compound, and crushing and drying to obtain the desired granular particle size.

Dusts containing the compounds are prepared simply by intimately mixing the compound in powdered form with a suitable dusty agricultural carrier, such as kaolin clay, ground volcanic rock and the like. Dusts can suitably contain from about 1% to about 10% of the compound.

It is equally practical, when desirable for any reason, to apply the compound in the form of a solution in an appropriate organic solvent, usually a bland petroleum oil, such as the spray oils, which are widely used in agricultural chemistry.

Insecticides and miticides are generally applied in the form of a dispersion of the active ingredient in a liquid carrier. It is conventional to refer to application rates in terms of the concentration of active ingredient in the carrier. The most widely used carrier is water.

The compounds of the invention can also be applied in the form of an aerosol composition. In such compositions the active compound is dissolved or dispersed in an inert carrier, which is a pressure-generating propellant mixture. The aerosol composition is packaged in a container from which the mixture is dispensed through an atomizing valve. Propellant mixtures comprise either low-boiling halocarbons, which may be mixed with organic solvents, or aqueous suspensions pressurized with inert gases or gaseous hydrocarbons.

The actual amount of compound to be applied to loci of insects and mites is not critical and can readily be determined by those skilled in the art in view of the examples above. In general, concentrations of from 10 ppm to 5000 ppm of compound are expected to provide good control. With many of the compounds, concentrations of from 100 to 1500 ppm will suffice. For field crops, such as soybeans and cotton, a suitable application rate for the compounds is about 0.5 to 1.5 lb/A, typically applied in 50 gal/A of spray formulation containing 1200 to 3600 ppm of compound. For citrus crops, a suitable application rate is from about 100 to 1500 gal/A spray formulation, which is a rate of 100 to 1000 ppm.

The locus to which a compound is applied can be any locus inhabited by an insect or arachnid, for example, vegetable crops, fruit and nut trees, grape vines, and ornamental plants. Inasmuch as many mite species are specific to a particular host, the foregoing list of mite species provides exemplification of the wide range of settings in which the present compounds can be used.

Because of the unique ability of mite eggs to resist toxicant action, repeated applications may be desirable to control newly emerged larvae, as is true of other known acaricides.

The following formulations of compounds of the invention are typical of compositions useful in the practice of the present invention.

    ______________________________________                                         A. 0.75 Emulsifiable Concentrate                                               N-[2-[4-( .sub.- t-butyl)phenyl]ethyl]-1,5-                                                           9.38%                                                   naphthyridin-4-amine                                                           "TOXIMUL D"            2.50%                                                   (nonionic/anionic surfactant blend)                                            "TOXIMUL H"            2.50%                                                   (nonionic/anionic surfactant blend)                                            "EXXON 200"            85.62%                                                  (naphthalenic solvent)                                                         B. 1.5 Emulsifiable Concentrate                                                4-(4-fluorophenoxy)-1,5-naphthyridine                                                                 18.50%                                                  "TOXIMUL D"            2.50%                                                   "TOXIMUL H"            2.50%                                                   "EXXON 200"            76.50%                                                  C. 0.75 Emulsifiable Concentrate                                               4-[2-[4-( .sub.- t-butyl)phenyl]ethoxy]-1,5-                                                          9.38%                                                   naphthyridine                                                                  "TOXIMUL D"            2.50%                                                   "TOXIMUL H"            2.50%                                                   "EXXON 200"            85.62%                                                  D. 1.0 Emulsifiable Concentrate                                                4-[2-[4-( .sub.- t-butyl)phenyl]ethoxy]-1,5-                                                          12.50%                                                  naphthyridine                                                                  N-methylpyrrolidone    25.00%                                                  "TOXIMUL D"            2.50%                                                   "TOXIMUL H"            2.50%                                                   "EXXON 200"            57.50                                                   E. 1.0 Aqueous Suspension                                                      4-[2-[4-( .sub.- t-butyl)phenyl]ethoxy]-1,5-                                                          12.00%                                                  naphthyridine                                                                  "PLURONIC P-103"       1.50%                                                   (block copolymer of propylene oxide                                            and ethylene oxide, surfactant)                                                "PROXEL GXL"           .05%                                                    (biocide/preservative)                                                         "AF-100"               .20%                                                    (silicon based antifoam agent)                                                 "REAX 88B"             1.00%                                                   (lignosulfonate dispersing agent)                                              propylene glycol       10.00%                                                  veegum                 .75%                                                    xanthan                .25%                                                    water                  74.25%                                                  F. 1.0 Aqueous Suspension                                                      N-[2-[4-( .sub.- t-butyl)phenyl]ethyl]-1,5-                                                           12.50%                                                  naphthyridine-4-amine                                                          "MAKON 10" (10 moles   1.00%                                                   ethyleneoxide nonylphenol surfactant)                                          "ZEOSYL 200" (silica)  1.00%                                                   "AF-100"               0.20%                                                   "AGRIWET FR" (surfactant)                                                                             3.00%                                                   2% xanthan hydrate     10.00%                                                  water                  72.30%                                                  G. 1.0 Aqueous Suspension                                                      4-[2-[4-( .sub.- t-butyl)phenyl]ethoxy]-1,5-                                                          12.50%                                                  naphthyridine                                                                  "MAKON 10"             1.50%                                                   "ZEOSYL 200" (silica)  1.00%                                                   "AF-100"               0.20%                                                   "POLYFON H"            0.20%                                                   (lignosulfonate dispersing agent)                                              2% xanthan hydrate     10.00%                                                  water                  74.60%                                                  H. Wettable Powder                                                             4-[2-[4-( .sub.- t-butyl)phenyl]ethoxy]-1,5-                                                          25.80%                                                  naphthyridine                                                                  "POLYFON H"            3.50%                                                   "SELLOGEN HR"          5.00%                                                   "STEPANOL ME DRY"      1.00%                                                   gum arabic             0.50%                                                   "HISIL 233"            2.50%                                                   Barden clay            61.70%                                                  I. Aqueous Suspension                                                          4-[2-[4-( .sub.- t-butyl)phenyl]ethoxy]-1,5-                                                          12.40%                                                  naphthyridine                                                                  "TERGITOL 158-7"       5.00%                                                   "ZEOSYL 200"           1.00%                                                   "AF-100"               0.20%                                                   "POLYFON H"            0.50%                                                   2% xanthan solution    10.00%                                                  tap water              70.90%                                                  J. Emulsifiable Concentrate                                                    4-[2-[4-( .sub.- t-butyl)phenyl]ethoxy]-1,5-                                                          12.40%                                                  naphthyridine                                                                  "TOXIMUL D"            2.50%                                                   "TOXIMUL H"            2.50%                                                   "EXXON 200"            82.60%                                                  K. Wettable Powder                                                             4-(4-fluorophenoxy)-1,5-naphthyridine                                                                 25.80%                                                  "SELLOGEN HR"          5.00%                                                   "POLYFON H"            4.00%                                                   "STEPANOL ME DRY"      2.00%                                                   "HISIL 233"            3.00%                                                   Barden clay            60.20%                                                  L. Emulsifiable Concentrate                                                    4-(4-fluorophenoxy)-1,5-naphthyridine                                                                 6.19%                                                   "TOXIMUL H"            3.60%                                                   "TOXIMUL D"            0.40%                                                   "EXXON 200"            89.81%                                                  M. Wettable Powder                                                             4-(4-fluorophenoxy)-1,5-naphthyridine                                                                 25.80%                                                  "SELLOGEN HR"          5.00%                                                   "POLYFON H"            4.00%                                                   "STEPANOL ME DRY"      2.00%                                                   "HISIL 233"            3.00%                                                   Barden clay            60.20%                                                  N. Aqueous Suspension                                                          N-[2-[4-( .sub.- t-butyl)phenyl]ethyl]-1,5-                                                           12.40%                                                  naphthyridin-4-amine                                                           "TERGITOL 158-7"       5.00%                                                   "ZEOSYL 200"           1.00%                                                   "POLYFON H"            0.50%                                                   "AF-100"               0.20%                                                   xanthan solution (2%)  10.00%                                                  tap water              70.90%                                                  ______________________________________                                     

We claim:
 1. A naphthyridine derivative of the formula (1) ##STR11## wherein one of A, B, E, or D is N, and the others are CR¹ ;R¹ and R² are independently H or halo; X is O, S, SO, SO₂, or CR⁴ R⁵, where R³ is H, (C₁ -C₄) alkyl, or (C₁ -C₄) acyl, and R⁴ and R⁵ are independently H, (C₁ -C₄) acyl, (C₁ -C₄)alkyl, (C₂ -C₄) alkenyl or -alkynyl, CN, or OH, or R⁴ and R⁵ combine to form a carbocyclic ring containing four to six carbon atoms; Y is nil, Z being directly bonded to X, or Y is an alkyl chain one to six carbon atoms long, optionally including a carbocyclic ring, and optionally including a hetero atom selected from O, S, SO, SO₂, NR³, or SiR¹⁹ R²⁰, where R¹⁹ and R²⁰ are independently H, (C₁ -C₄) alkyl, (C₃ -C₄) branched alkyl, phenyl, or substituted phenyl, and optionally substituted with (C₁ -C₄) alkyl, (C₂ -C₄) alkenyl or -alkynyl, (C₃ -C₇) branched alkyl, (C₃ -C₇) cycloalkyl or -cycloalkenyl, halo, hydroxy, or acetyl, and Z is (a) a phenyl group of the formula (2) ##STR12## where R⁶ to R¹⁰ are independently halo, I, (C₁ -C₁₀) alkyl, (C₃ -C₈) alkenyl or -alkynyl, branched (C₃ -C₆) alkyl, -alkenyl, or -alkynyl, (C₃ -C₈) cycloalkyl or -cycloalkenyl, halo (C₁ -C₇) alkyl, (C₁ -C₇) alkoxy, (C₁ -C₇) alkylthio, halo (C₁ -C₇) alkoxy, phenoxy, substituted phenoxy, phenylthio, substituted phenylthio, phenyl, substituted phenyl, NO₂, acetoxy, OH, CN, SiR¹¹ R¹² R¹³, OSiR¹¹ R¹² R¹³, NR¹⁴ R¹⁵, S(O)R¹⁶, or SO₂ R¹⁷ where R¹¹, R¹², and R¹³ are independently (C₁ -C₄) alkyl, (C₃ -C₄) branched alkyl, phenyl, or substituted phenyl, R¹⁴ and R¹⁵ are independently H, (C₁ -C₄) alkyl, or (C₁ -C₄) acyl, and R¹⁶ and R¹⁷ are phenyl, substituted phenyl, or (C₁ -C₄) alkyl; (b) a thienyl group of the formula (4) ##STR13## where R¹⁸ is as defined in paragraph (b); (c) a group of formula (5) or (6) ##STR14## where R¹⁸ is as defined in paragraph (b), J is N or CH, and G is O, NR¹⁹, or S, provided that if J is not N then G is NR¹⁹, where R¹⁹ is H, (C₁ -C₄) alkyl, (C₁ -C₄) acyl, phenylsulfonyl, or substituted phenylsulfonyl; (d) a group selected from optionally substituted naphthyl, dihydronaphthyl, tetrahydronaphthyl, and decahydronaphthyl; optionally substituted pyridyl; optionally substituted indolyl; and 1,3-benzodioxolyl; or an acid addition salt or N-oxide of a compound of formula (1).
 2. A compound of claim 1 wherein A is N.
 3. A compound of claim 1 wherein X is O.
 4. A compound of claim 1 wherein Y is C₂ H₄ and Z is a phenyl group of formula (2).
 5. A compound of claim 1 wherein B is N.
 6. A compound of claim 1 wherein C is N.
 7. A compound of claim 1 wherein D is N.
 8. A compound of claim 1 wherein R¹ and R² are H.
 9. A compound of claim 3 wherein Y is nil.
 10. A compound of claim 1 wherein Y is C₂ H₄.
 11. A compound of claim 1 wherein Z is a phenyl group of formula (2).
 12. A compound of the formula ##STR15## wherein X is O;Y is nil, CH₂, C₂ H₄, or C₃ H₆ ; and R⁶ to R¹⁰ are independently halo, I, (C₁ -C₁₉) alkyl, (C₃ -C₈) alkenyl or -alkynyl, branched (C₃ -C₆) alkyl, -alkenyl, or -alkynyl, (C₃ -C₈) cycloalkyl or -cycloalkenyl, halo (C₁ -C₇) alkyl, (C₁ -C₇) alkoxy, (C₁ -C₇) alkylthio, halo (C₁ -C₇) alkoxy, phenoxy, substituted phenoxy, phenylthio, substituted phenylthio, phenyl, substituted phenyl, NO₂, acetoxy, OH, CN, SiR¹¹ R¹² R¹³, OSiR¹¹ R¹² R¹³, NR¹⁴ R¹⁵, S(O)R¹⁶, or SO₂ R¹⁷ where R¹¹, R¹², and R¹³ are independently (C₁ -C₄) alkyl, (C₃ -C₄) branched alkyl, phenyl, or substituted phenyl, R¹⁴ and R¹⁵ are independently H, (C₁ -C₄) alkyl, or (C₁ -C₄) acyl, and R¹⁶ and R¹⁷ are phenyl, substituted phenyl, or (C₁ -C₄) alkyl.
 13. A compound of claim 12 wherein one of R⁶ to R¹⁰ is branched (C₃ -C₆) alkyl, halo (C₁ -C₄) alkyl, halo (C₁ -C₄) alkoxy, phenyl, substituted phenyl, phenoxy, substituted phenoxy, phenylthio, substituted phenylthio, SiR¹¹ R¹² R¹³ or OSiR¹¹ R¹² R¹³.
 14. A fungicidal method which comprises applying to the locus of a plant pathogen a disease inhibiting and phytologically acceptable amount of a compound of claim
 1. 15. A fungicide composition which comprises a compound of claim 1 in combination with a phytologically-acceptable carrier.
 16. A naphthyridine derivative of the formula ##STR16## wherein one of A, B, E, or D is N, and the others are CR¹ ;R¹ and R² are independently H or halo; X is O, S, SO, SO₂, or CR⁴ R⁵, where R³ is H, (C₁ -C₄) alkyl, or (C₁ -C₄) acyl, and R⁴ and R⁵ are independently H, (C₁ -C₄) acyl, (C₁ -C₄) alkyl, (C₂ -C₄) alkenyl or -alkynyl, CN, or OH, or R⁴ and R⁵ combine to form a carbocyclic ring containing four to six carbon atoms; Y is nil, Z being directly bonded to X, or Y is an alkyl chain one to six carbon atoms long, optionally including a carbocyclic ring, and optionally including a hetero atom selected from O, S, SO, SO₂, NR³, or SiR¹⁹ R²⁰, where R¹⁹ and R²⁰ are independently H, (C₁ -C₄) alkyl, (C₃ -C₄) branched alkyl, phenyl, or substituted phenyl, and optionally substituted with (C₁ -C₄) alkyl, (C₂ -C₄) alkenyl or -alkynyl, (C₃ -C₇) branched alkyl, (C₃ -C₇) cycloalkyl or -cycloalkenyl, halo, hydroxy, or acetyl, and Z is a phenyl group of the formula (2) ##STR17## wherein one of R⁶ to R¹⁰ is branched (C₃ -C₆) alkyl, halo (C₁ -C₄) alkyl, halo (C₁ -C₄) alkoxy, phenyl, substituted phenyl, phenoxy, substituted phenoxy, phenylthio, substituted phenylthio, SiR¹¹ R¹² R¹³ or OSiR¹¹ R¹² R¹³, where R¹¹, R¹², and R¹³ are independently (C₁ -C₄) alkyl, (C₃ -C₄) branched alkyl, phenyl, or substituted phenyl; or an acid addition salt or N-oxide of a compound of formula (1). 